Nonlinear behavior of concrete end diaphragms in straight slab-girder bridges

The seismic behavior of concrete end diaphragms of bridges has not been studied before and there are no signiffcant design provisions available. according to the american association of state highway and transportation officials (aashto), the end diaphragms being part of the seismic load path have to remain elastic under the prescribed seismic design forces, regardless of the type of bearings used. in this paper, using a threedimensional finite element model and nonlinear time history analyses, the behavior of reinforced concrete end diaphragms in straight single-span slab-girder bridges has been investigated. the results are compared to aashto's design provisions. it is concluded that for slab-girder concrete bridges, the concrete diaphragms remain elastic under design earthquake loading. it is also concluded that aashto's recommended seismic design forcefor end diaphragms could be unsafe in most cases.